This application claims benefit of Japanese Application No. 2000-69928 filed in Japan on Mar. 14, 2000, the contents of which are incorporated by this reference.
1. Field of the Invention
The present invention relates to a printer device, or more particularly, to a printer device that is so compact and lightweight as to be portable.
2. Description of Related Art
Personal computers and video recorders have been popular in recent years. Various types of printer devices capable of recording images produced by equipment including the personal computer and video recorder have been proposed, and the needs for printer devices have increased. There is therefore an increasing demand for a printer device that is inexpensive and capable of producing high-definition print images. Moreover, a portable printer device that is compact and lightweight is highly demanded along with the needs for a mobile printer device that permits printing at any time in any place.
In a typical thermal printer device, a color hard-copy ink sheet having three dyes of yellow (Y), magenta (M) and cyan (C) cyclically applied thereto in predetermined order is circulated based on a video signal sent from an information source. A thermal head is heated in order to sublimate the dyes on the ink sheet. Thus, one screen image is printed in colors on recording paper (thermal transfer recording paper). Moreover, in the printer device, the length of time during which current is fed to the thermal head is controlled in order to adjust the amounts of dyes to be sublimated. Gray scaling is thus controlled. After an image is recorded in this way, a recording paper transporting mechanism included in the printer device transports recorded recording paper, and feeds it to and stores it in, for example, a finished paper case. Thus, a recording process for one screen image (one page) is completed.
Even the above type of thermal printer device is demanded to be so compact and lightweight as to be portable. As a related art, a printer device has been proposed in Japanese Unexamined Patent Publication No. 11-157113.
In the proposed printer device, an ink ribbon having thermal transfer inks applied to a thin film and recording paper are transported while being pressed by a thermal head and a platen roller. Current is then fed to an exothermic resistor included in the thermal head, thus heating the exothermic resistor. The exothermic resistor transfers the thermal transfer inks on the ink ribbon onto the recording paper, whereby printing is achieved. The printer device is characterized in that a thermistor is used to measure temperature for the purpose of setting the next printing start time instant. Thus, the printer device is readily realized as a compact printer device having the features that the thermal head enjoys excellent beat efficiency and sheets of recording paper can be printed successively.
Moreover, the thermal head employed in the printer device includes a bar-like glass member that is attached along one edge of a printed-circuit board. An exothermic unit including a plurality of exothermic resistors is formed along the bar-like glass member. The exothermic resistors are connected to a plurality of independent electrodes and a common electrode. A thermistor connected to the common electrode and a plurality of driving ICs connected to each of the plurality of independent electrodes and the common electrodes are mounted on the printed-circuit board. Consequently, power consumed by the thermal head can be set to a small value. Besides, a radiating plated employed in the related art becomes unnecessary. Therefore, the thermal head can be adapted to a printer device that is so compact and lightweight as to be portable.
For realizing a portable printer device, it is, as already known, important to design the printer device to be compact and lightweight. Another important factor for realizing a portable printer device is whether the printer device can be driven for printing using only a battery as well as an ac power line. Moreover, it would be found user-friendly if a charge circuit for charging the battery is incorporated in the printer device.
The improved printing performance of the conventional printer device and the compact and lightweight design thereof have been attained by improving the thermal head and obviating the necessity of the radiating plate. No description has been made of where a circuit-printed board should be placed in practice or how circuit elements should be mounted on the circuit-printed board in practice in order to attain the compact and lightweight design of the entire printer device. This poses a problem in that the printer device cannot be designed fully compactly. Moreover, the battery that is an important component of a portable printer device and the charge circuit for charging the battery are not included in the conventional printer device. The conventional printer device therefore fails to satisfy users who want a portable printer device.
Accordingly, an object of the present invention is to provide a printer device that is so compact and lightweight as to be optimally portable.
A printer device in accordance with the present invention comprises a control printed-circuit board, a power printed-circuit board, and a coupling means. The control printed-circuit board is placed on the bottom of the printer device and includes a control circuit that controls at least one of a paper feed and an ink ribbon feed. The power printed-circuit board is placed along one side surface of the printer device, and includes a charge circuit that charges a rechargeable battery brought into contact with battery contact connected to the charge circuit. The coupling means electrically couples the control printed-circuit board to the power printed-circuit board.
According to the present invention, the control printed-circuit board including the control circuit that controls at least one of paper feed and ink ribbon feed is placed on the bottom of the printer device. The power printed-circuit board including the charge circuit is located along one side surface of the printer device. The charge circuit charges the rechargeable battery brought into contact with the power contacts connected to the charge circuit. The control printed-circuit board and the power printed-circuit board are electrically coupled to each other using the coupling means. Consequently, the printed-circuit boards and the placement of the printed-circuit boards are most suitable for the compact design of the printer device from a structural viewpoint.